The invention relates to a method for demodulating load-modified signals in a system and to a reading device (LES), which supplies a high-frequency carrier signal (ST) to a transmitting antenna (ANT). Passive transponders (TRA) located in the area of influence of the antenna (ANT) receive the signal and subject the received signal to a load modulation. The retroactive modulated HF signal is demodulated inside the reading device in order to evaluate the modulation signal. Auxiliary carriers (SH), which are shifted by a phase angle (f) and which are frequency-synchronous with the carrier signal (ST), are generated by means of an auxiliary signal transmitter (HSG), and carrier signals (ST) and auxiliary carriers (SH) are added in a summing circuit (SUM). Both the resulting sum signal (SR) as well as the carrier signal (ST) are subjected to an amplitude demodulation by means of a demodulator (DEI), and the demodulated signals (sI, sQ) are processed further for evaluation.
|Translated title of the contribution||METHOD FOR DEMODULATING AND READING DEVICE FOR EVALUATING LOAD-MODULATED SIGNALS|
|IPC||H04L 27/ 233 A I|
|Publication status||Published - 12 Oct 2006|